refactor encrypt; add cfb1 and cfb8 modes

tests/aes-cfb1.json

@@ -0,0 +1,10 @@
+{
+    "server":"127.0.0.1",
+    "server_port":8388,
+    "local_port":1081,
+    "password":"aes_password",
+    "timeout":60,
+    "method":"aes-256-cfb1",
+    "local_address":"127.0.0.1",
+    "fast_open":false
+}

tests/aes-cfb8.json

@@ -0,0 +1,10 @@
+{
+    "server":"127.0.0.1",
+    "server_port":8388,
+    "local_port":1081,
+    "password":"aes_password",
+    "timeout":60,
+    "method":"aes-256-cfb8",
+    "local_address":"127.0.0.1",
+    "fast_open":false
+}

tests/test.py

@@ -11,8 +11,8 @@ from subprocess import Popen, PIPE
 sys.path.insert(0, './')
 
 if 'salsa20' in sys.argv[-1]:
-    from shadowsocks import encrypt_salsa20
-    encrypt_salsa20.test()
+    from shadowsocks.crypto import salsa20_ctr
+    salsa20_ctr.test()
     print 'encryption test passed'
 
 p1 = Popen(['python', 'shadowsocks/server.py', '-c', sys.argv[-1]], stdin=PIPE,